It is known that the following method is used in order to perform the cross-linking of dental bridges, crowns or entire arches meant to replace missing teeth of a patient:
the dental surgeon prepares pillars (filed natural or artificial teeth) which support the entire prosthesis; PA1 then takes the impression (in silicone or other material) and gives it to the prosthodontics laboratory; PA1 the dental technician pours plaster into the impression so as to obtain the model on which the prosthesis is to be built; PA1 the metallic supporting structure is then prepared on the model (which represents the mouth of the patient). PA1 applying wax to a metallic supporting structure for a tooth, bridge or entire dental arch and manually modeling the wax so as to reconstruct the shape of the intended teeth; PA1 inserting said metal structure, with modeled wax applied thereto, in said container; PA1 injecting transparent silicone into said container, so as to surround said wax-covered metallic structure, embedding said structure in the silicone; PA1 mutually clamping the plate-like elements constituting said container in order to compress said transparent silicone and make it adhere to the wax that covers said metallic structure, so that said silicone, by curing, assumes the shape of the modeled wax, obtaining the mold; PA1 opening said container, removing the wax from said metallic structure and filling with composite materials the space freed by the removal of said wax; and PA1 placing said metallic structure, with the composite material on it, back into said container and exposing said container to a photopolymerization machine in order to cure said composite materials and produce the intended prosthesis.
A photopolymerizable composite material is applied directly to the metallic structure that constitutes the support for the teeth forming the dental prosthesis to be produced; said material is modeled manually in order to produce the correct shape and size of the individual teeth composing the prosthesis.
This manual treatment of the composite material, besides being extremely difficult from the practical point of view since the composite material can sometimes be very hard and therefore requiring highly specialized personnel, is considerably expensive in terms of time and costs.
In order to model a prosthesis which is constituted for example by a single tooth or by a pair of teeth, i.e., a prosthesis that covers a limited portion of the dental arch, this drawback can be obviated by providing a plaster template which is used to shape the composite material.
This solution, however, is not applicable if a prosthesis is to be obtained that covers a considerable extent of the dental arch, since the plaster pattern must adhere and be shaped according to the metallic supporting structure but its rigidity prevents it from doing so.
A partial solution to this problem might consist in providing the plaster pattern in two or three parts, but it has been observed that in this case it is very difficult to adjust each part of the plaster pattern with the same pressure and in the same position in order to achieve correct shaping of the composite material.